1. Field of the Invention
The present invention relates to a muffler for use in an engine exhaust system, and to a construction machine, such as a hydraulic shovel, which includes a muffler mounting device for mounting the muffler to a frame of the machine.
2. Description of the Related Art
The background art will be described by taking a hydraulic shovel as an example.
FIG. 6 shows an upper rotating body mounted on a lower running body. Referring to FIG. 6, an operating attachment (not shown) including a boom, an arm, and a bucket is attached to one end (left end in the figure; hereinafter a side of the left end indicates the front side) of an upper frame 1 of the upper rotating body.
On an upper surface of the upper frame 1, vertical plates (sometimes referred to as main frames) 2 and 3 serving as strong members are provided on both left and right sides of the center in the left-right direction. The vertical plates 2 and 3 extend over the substantially entire length in the front-rear direction. On the upper surface of the upper frame 1, partition walls 4, 5, and 6 also extend in the front-rear direction in the rear of the upper frame 1. An engine room 7 is provided in a rear end portion of the upper frame 1 defined by the partition walls 4, 5, and 6.
In the engine room 7, an engine 8 is provided between the left and right vertical plates 2 and 3. On the left side of the engine 8, a cooling fan 9 and a heat exchanger 10, such as an intercooler, a radiator, or an oil cooler, are provided as cooling equipment.
On the right side of the engine 8, a hydraulic pump 11 is provided while being connected to an engine output shaft. A muffler 12 crosses above the hydraulic pump 11.
As a mounting device for the muffler 12, a muffler mount 13 overhangs from a fixed portion of the machine (e.g., a pump-side outer wall of the engine 8), and the muffler 12 is mounted on the muffler mount 13 by a U-bolt 14, as shown in FIG. 7 (see Japanese Unexamined Patent Application Publication Nos. 2003-104071 and 10-317957).
However, when the muffler 12 is mounted on the muffler mount 13 by the U-bolt, as in the related art, the clamping force of the U-bolt 14 directly acts on the outer periphery of the muffler 12, and the mounting portion is therefore susceptible to damage.
In a typical muffler, a silencer is coupled to each side of an exhaust-gas purifying device containing a catalyst. For this reason, if the exhaust-gas purifying device is clamped by a U-bolt, not only the outer periphery of the device, but also contents (catalyst) may be damaged by the clamping force.